Reduced diameter ruggedized fiber optic distribution cables

ABSTRACT

A fiber optic distribution cable includes a central inner jacket formed from one of a polyvinyl chloride or a low smoke zero halogen material, a plurality of optical fibers disposed within the inner jacket, and a plurality of first strength members disposed within the inner jacket. The fiber optic distribution cable further includes an outer jacket surrounding the central inner jacket, the outer jacket formed from the one of the polyvinyl chloride or the low smoke zero halogen material, and a plurality of second strength members disposed between the outer jacket and the central inner jacket. A fiber density of the cable is greater than 0.65 fibers per square millimeter.

This application is a continuation of U.S. patent application Ser. No.16/908,121, filed on Jun. 22, 2020, which is a continuation of U.S.patent application Ser. No. 16/478,064, filed on Jul. 15, 2019, which isa National Stage Patent Application of PCT/US2017/014858, filed on Jan.25, 2017, the disclosures of which are incorporated by reference hereinin their entireties.

FIELD OF THE INVENTION

The present disclosure relates generally to fiber optic distributioncables, and more particularly to fiber optic distribution cables havingincreased fiber densities and reduced associated diameters.

BACKGROUND OF THE INVENTION

Optical fiber distribution cables are utilized in building/campus localarea networks, central offices, data centers and other premises wherehigh bandwidth data transfer is required. These cables can be deployedin both overhead and raised floor cable pathways, along withterminations into data cabinets. As data transfer requirements haveincreased, the number of fibers to support these demands has driven thedevelopment of high fiber density products. High density micro-cablingalong with multi-fiber connectivity have been instrumental in supportingthe increasing demands for high bandwidth data transfer.

Known distribution cables are typically sub-unitized and include acentral strength member. However, while many such distribution cablesare useful and provide the desired performance characteristics,improvements in distribution cable design are desired. For example,increased flexibility and fiber density are desired to provide improvedinstallation and optical transmission capabilities. However, theruggedness and relatively small overall size of the cables mustdesirable be maintained.

Accordingly, improved fiber optic distribution cables are desired in theart.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In accordance with one embodiment, a fiber optic distribution cable isprovided. The fiber optic distribution cable includes a central innerjacket formed from one of a polyvinyl chloride or a low smoke zerohalogen material, a plurality of optical fibers disposed within theinner jacket, and a plurality of first strength members disposed withinthe inner jacket. The fiber optic distribution cable further includes anouter jacket surrounding the central inner jacket, the outer jacketformed from the one of the polyvinyl chloride or the low smoke zerohalogen material, and a plurality of second strength members disposedbetween the outer jacket and the central inner jacket. A fiber densityof the cable is greater than 0.65 fibers per square millimeter.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 is a cross-sectional view of a fiber optic distribution cable inaccordance with embodiments of the present disclosure;

FIG. 2 is a top view of a plurality of optical fibers utilized in afiber optic distribution cable in accordance with some embodiments ofthe present disclosure; and

FIG. 3 is a top view of a plurality of optical fibers utilized in afiber optic distribution cable in accordance with other embodiments ofthe present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

Referring now to FIG. 1 , a fiber optic distribution cable 10 inaccordance with embodiments of the present disclosure is provided. Cable10 includes an inner jacket 12, and a plurality of optical fibers 14disposed within the inner jacket 12. Additionally, a plurality of firststrength members 16 may be disposed within the inner jacket 12. An outerjacket 18 may surround the inner jacket 12, and a plurality of secondstrength members 20 may be disposed between the outer jacket 18 and theinner jacket 12.

The inner jacket 12 is, as shown, a central inner jacket 12 which thusgenerally encompasses a center point of the cable 10 in across-sectional view. Further, as shown, only a single inner jacket 12is utilized. In other words, only a single sub-unit, rather thanmultiple sub-units, is utilized in cable 10. All optical fibers 14utilized in cable 10 are thus disposed within inner jacket 12. The innerjacket 12 has a generally continuous tubular cross-sectional shape, asshown.

The inner jacket 12 may be formed from one of a polyvinyl chloride or alow smoke zero halogen material. In some embodiments, for example, theinner jacket 12 may be formed from a polyvinyl chloride. In exemplaryembodiments, the inner jacket 12, and thus the material utilized to formthe inner jacket 12, may be riser-rated or plenum-rated. For example,the inner jacket 12 and material thereof may have a flame rating ofOFNR-LS/FT4 (riser-rated) (with, for example, a flame propagationcharacteristic of less than 12 feet) or OFNP/FT6 (plenum-rated) (with,for example, a flame propagation characteristic of less than 5 feet). Inalternative embodiments, the inner jacket 12 may be formed from a lowsmoke zero halogen material, which may for example, include a polyolefinsuch as polyethylene. In exemplary embodiments, the inner jacket 12 andmaterial thereof may have a flame rating of OFNR-LS/FT4 (with, forexample, a flame propagation characteristic of less than 12 feet).

The outer jacket 18 also has a generally continuous tubularcross-sectional shape, as shown. The outer jacket 18, which may be theoutermost exterior layer of the cable 10, may be formed from the samematerial as the inner jacket 12. Accordingly, the outer jacket 18 may beformed from one of a polyvinyl chloride or a low smoke zero halogenmaterial. In some embodiments, for example, the outer jacket 18 may beformed from a polyvinyl chloride. In exemplary embodiments, the outerjacket 18, and thus the material utilized to form the outer jacket 18,may be riser-rated or plenum-rated. For example, the outer jacket 18 andmaterial thereof may have a flame rating of OFNR-LS/FT4 (riser-rated)(with, for example, a flame propagation characteristic of less than 12feet) or OFNP/FT6 (plenum-rated) (with, for example, a flame propagationcharacteristic of less than 5 feet). In alternative embodiments, theouter jacket 18 may be formed from a low smoke zero halogen material,which may for example, include a polyolefin such as polyethylene. Inexemplary embodiments, the outer jacket 18 and material thereof may havea flame rating of OFNR-LS/FT4 (with, for example, a flame propagationcharacteristic of less than 12 feet).

As discussed, first strength members 16 may be disposed within the innerjacket 12, and second strength members 20 may be disposed between theouter jacket 18 and inner jacket 12. In exemplary embodiments, the firststrength members 16 and second strength members 20 may be fibers, suchas aramid fibers or other suitable fibers utilized for strengthpurposes. It should be noted that, in exemplary embodiments as shown, noadditional components or materials, aside from second strength members20 and optional binders or ripcords, may be provided in the spacebetween the outer jacket 18 and inner jacket 12. Such space may thus,for example, be free from gels, additional intervening jackets or othertubes, etc. Similarly, in exemplary embodiments as shown, no additionalcomponents or materials, aside from first strength members 16 andoptical fibers 14 as discussed herein, may be provided within innerjacket 12.

Any suitable optical fibers 14 may be utilized in cable 10. For example,the optical fibers 16 may be single mode optical fibers or multi-modeoptical fibers. Further, in some embodiments, the optical fibers 14 mayhave nominal (plus or minus 3 microns) outer diameters of 250 microns.In alternative embodiments, the optical fibers 14 may have nominal outerdiameters of 200 microns. In some embodiments, as illustrated in FIG. 2, the optical fibers 14 may be loose optical fibers which are notribbonized or otherwise bonded to each other. In alternativeembodiments, the optical fibers 14 may be ribbonized to form one or moreribbons. For example, in some embodiments as illustrated in FIG. 3 , theoptical fibers 14 may be intermittently bonded to each other (via, forexample, portions of the outermost jacket or layer of the optical fibers14), thus forming one or more ribbons. Such intermittent bonding mayoccur along the lengths of the optical fibers 14, thus leavingnon-bonded gaps between neighboring optical fibers 14 as shown. Further,the bonded portions 15 of neighboring optical fibers 14 may be staggeredalong the lengths of the optical fibers 14 such that neighboring opticalfibers 14 in a ribbon are bonded to each other at different locationsalong their lengths and the length of the ribbon.

Referring again to FIG. 1 , cables 10 in accordance with the presentdisclosure may advantageously have relatively high fiber densities. Asutilized herein, fiber density is the total number of optical fibers ina cable 10 divided by the cross-sectional area of the cable 10. Thecross-sectional area may be calculated as pi times the square of themaximum radius of the cable 10, and the maximum radius may be half ofthe maximum outer diameter 30 of the outer jacket 18. Further, cables 10in accordance with the present disclosure may have such relatively highfiber densities while advantageously meeting the OFNR-LS/FT4, OFNP/FT6,and/or OFNR-LS/FT4 requirements. Meeting such requirements may requirethat wall thicknesses 32, 34 of the inner jacket 12 and outer jacket 18,respectively, may be relatively high for relatively low maximum outerdiameters 30 and maximum outer diameters 36 of the inner jacket 12, thusfurther illustrating the advantageously high fiber densities achieved inaccordance with the present disclosure. For example, as discussed hereinand depending on the outer diameter 30, the inner jacket 12 may have awall thickness 32 of between 0.35 and 1.1 millimeters, and the outerjacket 18 may have a wall thickness 34 of between 0.5 and 1.4millimeters.

In some embodiments, the maximum outer diameter 30 may be less than orequal to 5 millimeters, such as less than or equal to 4.9 millimeters,such as between 4.9 millimeters and 4.7 millimeters, such as 4.8millimeters. In these embodiments and when 250 nominal diameter micronoptical fibers 14 are utilized, the fiber density may be between 0.65and 1.35 fibers per square millimeter, such as between 0.66 and 1.33fibers per square millimeter. Such embodiments may, for example, utilizebetween 10 and 25 optical fibers 14, such as in some embodiments 12, 16,or 24 optical fibers 14. For example, in embodiments wherein 12 opticalfibers 14 are utilized, the fiber density may be between 0.65 and 0.67fibers per square millimeter, such as between 0.66 and 0.665 fibers persquare millimeter. In embodiments wherein 16 optical fibers 14 areutilized, the fiber density may be between 0.87 and 0.89 fibers persquare millimeter, such as between 0.88 and 0.885 fibers per squaremillimeter. In embodiments wherein 24 optical fibers 14 are utilized,the fiber density may be between 1.31 and 1.34 fibers per squaremillimeter, such as between 1.32 and 1.33 fibers per square millimeter.

Further, in these embodiments, the inner jacket 12 may have a wallthickness 32 of between 0.35 and 0.45 millimeters, such as 0.4millimeters. The outer jacket 18 may have a wall thickness 34 of between0.5 and 0.6 millimeters, such as 0.55 millimeters. The maximum outerdiameter 36 of the inner jacket 12 may be between 2.8 and 3.2millimeters, such as between 2.9 and 3.1 millimeters, such as 3millimeters.

In other embodiments, the maximum outer diameter 30 may be less than orequal to 5.8 millimeters, such as less than or equal to 5.7 millimeters,such as between 5.7 millimeters and 5.5 millimeters, such as 5.6millimeters. In these embodiments and when 250 nominal diameter micronoptical fibers 14 are utilized, the fiber density may be between 1.45and 1.95 fibers per square millimeter. Such embodiments may, forexample, utilize between 30 and 50 optical fibers 14, such as in someembodiments 36 or 48 optical fibers 14. For example, in embodimentswherein 36 optical fibers 14 are utilized, the fiber density may bebetween 1.45 and 1.48 fibers per square millimeter, such as between 1.46and 1.47 fibers per square millimeter. In embodiments wherein 48 opticalfibers 14 are utilized, the fiber density may be between 1.93 and 1.95fibers per square millimeter, such as between 1.94 and 1.95 fibers persquare millimeter.

Further, in these embodiments, the inner jacket 12 may have a wallthickness 32 of between 0.5 and 0.6 millimeters, such as 0.55millimeters. The outer jacket 18 may have a wall thickness 34 of between0.55 and 0.65 millimeters, such as 0.6 millimeters. The maximum outerdiameter 36 of the inner jacket 12 may be between 3.6 and 4.2millimeters, such as between 3.7 and 4.1 millimeters, such as 3.8millimeters or 4 millimeters.

In other embodiments, the maximum outer diameter 30 may be less than orequal to 6.5 millimeters, such as less than or equal to 6.4 millimeters,such as between 6.1 millimeters and 6.5 millimeters, such as 6.2millimeters or 6.4 millimeters. In these embodiments and when 250nominal diameter micron optical fibers 14 are utilized, the fiberdensity may be between 2.1 and 2.25 fibers per square millimeter. Suchembodiments may, for example, utilize between 60 and 80 optical fibers14, such as in some embodiments 64 or 72 optical fibers 14. For example,in embodiments wherein 64 optical fibers 14 are utilized, the fiberdensity may be between 2.0 and 2.2 fibers per square millimeter, such asbetween 2.1 and 2.15 fibers per square millimeter. In embodimentswherein 72 optical fibers 14 are utilized, the fiber density may bebetween 2.1 and 2.3 fibers per square millimeter, such as between 2.2and 2.25 fibers per square millimeter.

Further, in these embodiments, the inner jacket 12 may have a wallthickness 32 of between 0.65 and 0.85 millimeters, such as 0.7millimeters or 0.8 millimeters. The outer jacket 18 may have a wallthickness 34 of between 0.65 and 0.75 millimeters, such as 0.7millimeters. The maximum outer diameter 36 of the inner jacket 12 may bebetween 4.3 and 5 millimeters, such as between 4.4 and 4.9 millimeters,such as 4.5 millimeters or 4.8 millimeters.

In other embodiments, the maximum outer diameter 30 may be less than orequal to 10.2 millimeters, such as less than or equal to 10.1millimeters, such as between 7.5 millimeters and 10.1 millimeters, suchas 7.8 millimeters or 9 millimeters or 10 millimeters. In theseembodiments and when 250 nominal diameter micron optical fibers 14 areutilized, the fiber density may be between 1.65 and 2.05 fibers persquare millimeter. Such embodiments may, for example, utilize between 90and 150 optical fibers 14, such as in some embodiments 96, 108, or 144optical fibers 14. For example, in embodiments wherein 96 optical fibers14 are utilized, the fiber density may be between 1.9 and 2.1 fibers persquare millimeter, such as between 2 and 2.02 fibers per squaremillimeter. In embodiments wherein 108 optical fibers 14 are utilized,the fiber density may be between 1.66 and 1.74 fibers per squaremillimeter, such as between 1.68 and 1.7 fibers per square millimeter.In embodiments wherein 144 optical fibers 14 are utilized, the fiberdensity may be between 1.8 and 1.85 fibers per square millimeter, suchas between 1.82 and 1.84 fibers per square millimeter.

Further, in these embodiments, the inner jacket 12 may have a wallthickness 32 of between 0.75 and 1.1 millimeters, such as 0.8millimeters or 0.9 millimeters or 1 millimeter. The outer jacket 18 mayhave a wall thickness 34 of between 0.85 and 1.35 millimeters, such as0.9 millimeters, 1.2 millimeters, or 1.3 millimeters. The maximum outerdiameter 36 of the inner jacket 12 may be between 5.6 and 7.4millimeters, such as between 5.7 and 7.3 millimeters, such as 5.8millimeters, 6.2 millimeters, or 7.2 millimeters.

Table 1 below provides various dimensions for cables 10 in accordancewith exemplary embodiments of the present disclosure:

TABLE 1 Cable Dimensions (250 micron optical fiber nominal diameter) #of Optical Inner Outer Fibers (250 Inner Jacket Wall Outer Jacket WallFiber micron) Jacket OD Thickness jacket OD Thickness density  12 3.00.40  4.80 0.55 0.663  16 3.0 0.40  4.80 0.55 0.884  24 3.0 0.40  4.800.55 1.326  36 3.8 0.55  5.60 0.60 1.462  48 4.0 0.55  5.60 0.60 1.949 64 4.5 0.70  6.20 0.70 2.120  72 4.8 0.80  6.40 0.70 2.238  96 5.8 0.80 7.80 0.90 2.009 108 6.2 0.90  9.00 1.20 1.698 144 7.2 1.00 10.00 1.301.833

In some embodiments, the maximum outer diameter 30 may be less than orequal to 5 millimeters, such as less than or equal to 4.8 millimeters,such as less than or equal to 4.6 millimeters, such as between 4.8millimeters and 4.3 millimeters, such as between 4.6 millimeters and 4.4millimeters, such as 4.5 millimeters. In these embodiments and when 200nominal diameter micron optical fibers 14 are utilized, the fiberdensity may be between 0.75 and 2.27 fibers per square millimeter, suchas between 0.753 and 2.267 fibers per square millimeter. Suchembodiments may, for example, utilize between 10 and 40 optical fibers14, such as in some embodiments 12, 16, 24, or 36 optical fibers 14. Forexample, in embodiments wherein 12 optical fibers 14 are utilized, thefiber density may be between 0.75 and 0.76 fibers per square millimeter,such as between 0.753 and 0.757 fibers per square millimeter. Inembodiments wherein 16 optical fibers 14 are utilized, the fiber densitymay be between 1 and 1.05 fibers per square millimeter, such as between1.002 and 1.01 fibers per square millimeter. In embodiments wherein 24optical fibers 14 are utilized, the fiber density may be between 1.5 and1.52 fibers per square millimeter, such as between 1.505 and 1.51 fibersper square millimeter. In embodiments wherein 36 optical fibers 14 areutilized, the fiber density may be between 2.26 and 2.27 fibers persquare millimeter, such as between 1.505 and 1.51 fibers per squaremillimeter.

Further, in these embodiments, the inner jacket 12 may have a wallthickness 32 of between 0.35 and 0.6 millimeters, such as 0.4millimeters or 0.55 millimeters. The outer jacket 18 may have a wallthickness 34 of between 0.5 and 0.6 millimeters, such as 0.55millimeters. The maximum outer diameter 36 of the inner jacket 12 may bebetween 2.8 and 3.2 millimeters, such as between 2.9 and 3.1millimeters, such as 3 millimeters.

In some embodiments, the maximum outer diameter 30 may be less than orequal to 5.8 millimeters, such as less than or equal to 5.7 millimeters,such as between 5.8 millimeters and 5.4 millimeters, such as between 5.7millimeters and 5.5 millimeters, such as 5.6 millimeters. In theseembodiments and when 200 nominal diameter micron optical fibers 14 areutilized, the fiber density may be between 1.94 and 2.95 fibers persquare millimeter, such as between 1.945 and 2.93 fibers per squaremillimeter. Such embodiments may, for example, utilize between 30 and 80optical fibers 14, such as in some embodiments 48, 64, or 72 opticalfibers 14. For example, in embodiments wherein 48 optical fibers 14 areutilized, the fiber density may be between 1.94 and 1.96 fibers persquare millimeter, such as between 1.945 and 1.95 fibers per squaremillimeter. In embodiments wherein 64 optical fibers 14 are utilized,the fiber density may be between 2.58 and 2.61 fibers per squaremillimeter, such as between 2.59 and 2.6 fibers per square millimeter.In embodiments wherein 72 optical fibers 14 are utilized, the fiberdensity may be between 2.85 and 2.95 fibers per square millimeter, suchas between 2.9 and 2.93 fibers per square millimeter.

Further, in these embodiments, the inner jacket 12 may have a wallthickness 32 of between 0.5 and 0.6 millimeters, such as 0.55millimeters. The outer jacket 18 may have a wall thickness 34 of between0.65 and 0.75 millimeters, such as 0.7 millimeters. The maximum outerdiameter 36 of the inner jacket 12 may be between 3.6 and 4 millimeters,such as between 3.7 and 3.9 millimeters, such as 3.8 millimeters.

In some embodiments, the maximum outer diameter 30 may be less than orequal to 7.6 millimeters, such as less than or equal to 7.5 millimeters,such as between 7.6 millimeters and 6 millimeters, such as between 7.55millimeters and 6.1 millimeters, such as 6.2 millimeters, 6.4millimeters, or 7.5 millimeters. In these embodiments and when 200nominal diameter micron optical fibers 14 are utilized, the fiberdensity may be between 3.16 and 3.36 fibers per square millimeter, suchas between 3.17 and 3.359 fibers per square millimeter. Such embodimentsmay, for example, utilize between 90 and 150 optical fibers 14, such asin some embodiments 96, 108, or 144 optical fibers 14. For example, inembodiments wherein 96 optical fibers 14 are utilized, the fiber densitymay be between 3.16 and 3.2 fibers per square millimeter, such asbetween 3.17 and 3.19 fibers per square millimeter. In embodimentswherein 108 optical fibers 14 are utilized, the fiber density may bebetween 3.35 and 3.36 fibers per square millimeter, such as between3.354 and 3.359 fibers per square millimeter. In embodiments wherein 144optical fibers 14 are utilized, the fiber density may be between 3.25and 3.27 fibers per square millimeter, such as between 3.255 and 3.26fibers per square millimeter.

Further, in these embodiments, the inner jacket 12 may have a wallthickness 32 of between 0.65 and 0.85 millimeters, such as 0.7millimeters or 0.8 millimeters. The outer jacket 18 may have a wallthickness 34 of between 0.65 and 0.95 millimeters, such as 0.7millimeters or 0.9 millimeters. The maximum outer diameter 36 of theinner jacket 12 may be between 4.3 and 5.6 millimeters, such as between4.4 and 5.5 millimeters, such as 4.5 millimeters, 4.8 millimeters, or5.4 millimeters.

Table 2 below provides various dimensions for cables 10 in accordancewith exemplary embodiments of the present disclosure:

TABLE 2 Cable Dimensions (200 micron optical fiber nominal diameter) #of Optical Inner Inner Outer Outer Fibers (200 Jacket Jacket Wall jacketJacket Wall Fiber micron) OD Thickness OD Thickness density 12 3.0 0.554.50 0.55 0.755 16 3.0 0.40 4.50 0.55 1.006 24 3.0 0.40 4.50 0.55 1.50936 3.0 0.40 4.50 0.55 2.264 48 3.8 0.55 5.60 0.70 1.949 64 3.8 0.55 5.600.70 2.598 72 3.8 0.55 5.60 0.70 2.923 96 4.5 0.70 6.20 0.70 3.180 1084.8 0.80 6.40 0.70 3.357 144 5.4 0.80 7.50 0.90 3.259

Cables 10 in accordance with the present disclosure may furtheradvantageously meet various Telecordia GR-409 Core Horizontal Backbonestandard (GR-409 Issue 2, November 2008) requirements. In particular,such cables 10 may meet the GR-409 requirements for outer jacketshrinkage, compressive strength, tensile strength, temperature cycling,low-high temperature bend, impact resistance, cable twist, and/or cyclicflexing. For example, in some embodiments, a cable 10 in accordance withthe present disclosure may have a tensile strength of up to or at least150 pounds. In some embodiments, a cable 10 in accordance with thepresent disclosure may exhibit an attenuation change of less than orequal to 0.03 dB, such as 0.02 dB when subjected to 4 bends around a 7inch diameter mandrel and with a 12.5 kg weight suspended at the end ofthe 4 wraps at −10, 0, 60, or 70° C. In some embodiments, a cable 10 inaccordance with the present disclosure may exhibit an attenuation changeof less than or equal to 0.003 dB, such as 0.002 dB, when subjected to25 cycles in a 180 degree arc (90 degrees clockwise and 90 degreescounterclockwise) with a 4 kg load attached to the end. In someembodiments, a cable 10 in accordance with the present disclosure mayexhibit an attenuation change of less than or equal to 0.006 dB, such as0.005 dB, when subjected to a minimum of 10 cycles of being twisted 180degrees clockwise and counter-clockwise. In some embodiments, a cable 10in accordance with the present disclosure may exhibit an attenuationchange of less than or equal to 0.17 dB, such as less than or equal to0.16 dB, when subjected to a compressive load of at least 100 N/cm overa period of 10 minutes, with the load applied at an increase of 3 to 20mm per minute. In some embodiments, a cable 10 in accordance with thepresent disclosure may exhibit an attenuation change of less than orequal to 0.003 dB, such as less than or equal to 0.002 dB, whensubjected to 2 impacts at 3 locations (which are 150 mm apart) of a dropforce of 2.94 Nm from a height of 150 mm. In some embodiments, a cable10 in accordance with the present disclosure may exhibit an attenuationchange of less than or equal to 0.5 dB, such as less than or equal to0.3 dB (single mode fiber) or less than or equal to 0.4 dB (multi-modefiber) when subjected to extreme temperatures over 120 hours rangingfrom −20° C. to 70° C. (for plenum-rated cables) or −40° C. to 70° C.(for LSZH cables), including a rate of change of temperature of 40degrees per hour and multiple exposure cycles at the extremetemperatures for 24 continuous hours within the 120 hours.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A fiber optic distribution cable, comprising: acentral inner jacket; a plurality of optical fibers disposed within theinner jacket, wherein at least some of the plurality of optical fibersare intermittently bonded into one or more ribbons; a plurality of firststrength members disposed within the inner jacket; an outer jacketsurrounding the central inner jacket; and a plurality of second strengthmembers disposed between the outer jacket and the central inner jacket,wherein the inner jacket and the outer jacket are formed from apolyolefin.
 2. The fiber optic distribution cable of claim 1, whereinoptical fibers of each of the one or more ribbons are intermittentlybonded together by bonded portions, and wherein the bonded portions arespaced apart from one another along the lengths of the optical fibers.3. The fiber optic distribution cable of claim 2, wherein the bondedportions of neighboring optical fibers are staggered along the lengthsof the optical fibers.
 4. The fiber optic distribution cable of claim 1,wherein others of the plurality of optical fibers are loose opticalfibers.
 5. A fiber optic distribution cable, comprising: a central innerjacket formed from one of a polyvinyl chloride or a low smoke zerohalogen material; a plurality of optical fibers disposed within theinner jacket, wherein at least some of the plurality of optical fibersare intermittently bonded into one or more ribbons; a plurality of firststrength members disposed within the inner jacket; an outer jacketsurrounding the central inner jacket, the outer jacket formed from theone of the polyvinyl chloride or the low smoke zero halogen material;and a plurality of second strength members disposed between the outerjacket and the central inner jacket, wherein the fiber density isbetween 1.45 and 2.25 fibers per square millimeter and the plurality ofoptical fibers is between 30 and 80 optical fibers.
 6. The fiber opticdistribution cable of claim 1, wherein the fiber density is between 1.45and 1.95 fibers per square millimeter and the plurality of opticalfibers is between 30 and 50 optical fibers.
 7. The fiber opticdistribution cable of claim 1, wherein the outer jacket has a maximumouter diameter of less than or equal to 5.8 millimeters and the fiberdensity is between 1.45 and 1.95 fibers per square millimeter.
 8. Thefiber optic distribution cable of claim 1, wherein the outer jacket hasa maximum outer diameter of less than or equal to 6.5 millimeters andthe fiber density is between 2.1 and 2.25 fibers per square millimeter.9. The fiber optic distribution cable of claim 1, wherein the pluralityof optical fibers have nominal outer diameters of 250 microns.
 10. Thefiber optic distribution cable of claim 1, wherein the inner jacket hasa wall thickness of between 0.35 and 1.1 millimeters.
 11. The fiberoptic distribution cable of claim 10, wherein the outer jacket has awall thickness of between 0.5 and 1.4 millimeters.
 12. The fiber opticdistribution cable of claim 1, wherein the inner jacket and the outerjacket are one of riser-rated or plenum-rated.
 13. The fiber opticdistribution cable of claim 1, wherein the cable has a tensile strengthof greater than or equal to 150 pounds.
 14. A fiber optic distributioncable comprising: a central inner jacket; a plurality of optical fibersdisposed within the inner jacket, wherein the plurality of opticalfibers are intermittently bonded into one or more ribbons; a pluralityof first strength members disposed within the inner jacket; an outerjacket surrounding the central inner jacket; and a plurality of secondstrength members disposed between the outer jacket and the central innerjacket, wherein optical fibers of each of the one or more ribbons areintermittently bonded together by bonded portions, wherein the bondedportions are spaced apart from one another along the lengths of theoptical fibers, and wherein the inner jacket and the outer jacket areformed from a polyolefin.
 15. The fiber optic distribution cable ofclaim 14, wherein the bonded portions of neighboring optical fibers arestaggered along the lengths of the optical fibers.
 16. The fiber opticdistribution cable of claim 14, wherein the inner jacket and the outerjacket are one of riser-rated or plenum-rated.
 17. The fiber opticdistribution cable of claim 14, wherein the cable has a tensile strengthof greater than or equal to 150 pounds.